A research team in Beligum has been testing a new method of determining brain activity in patients, such as those in a coma, to help objectively determine if they're brain dead.

It is a difficult thing to determine if a brain-injured person is conscious or not; where does one draw the line between alive and dead? This question is something doctors have to deal with every day, when deciding whether or not they are observing reflexes or actual, purposeful responses, to stimuli on vegetative patients. It's really an open question, and each doctor has to make that call subjectively.

There have been several attempts at finding a generalized test to determine if a person truly is conscious, such as doing EEG scans of brain activity. But even here, the results aren't always black and white: Several years ago, an unconscious and vegetative patient was found to be able to answer yes or no questions as well as any alert and awake person.

Example of the kind of system used for monitoring brain activity

Melanie Boly, postdoc at the Belgian National Fund for Research in Liege, has been hard at work to find a new method of testing patents that can empirically decide whether they are in fact conscious. A team of 32 volunteers were subjected to a short electrical pulse on their brains, after which the brain activity was monitored. In awake patients, the pulse caused a response of activity which spread across the brain. In healthy, but sleeping patients, the response was similar but shorter.

As Boly performed the test on vegetative patients, the result was similar to that of the sleeping volunteers, and she found that the more conscious they were, the more complex the brain activity response. This "response complexity index" could thus help determine consciousness of patients in the future.